Cesium Ions Research Articles

Highly-selective and well-effective removal of cesium ions by segregative titanium-ferrocyanide/chitosan melamine sponge composite

Selectively and efficiently removing Cs is of great urgency and challenge for the treatment of radioactive wastewater. In this work, titanium-ferrocyanide/chitosan melamine sponge composite (TFCM) was synthesized by cross-linking and titanium-doping strategy, and employed to remove Cs+ from water. The obtained TFCM exhibited excellent adsorption performance for Cs+, due to its porous and 3D skeleton structure. The TFCM demonstrated a broad range of pH (pH = 3–11) suitability and high removal ratio of Cs+. The adsorption behavior of TFCM on Cs+ conformed to the Langmuir adsorption process and pseudo-second-order kinetics model. Remarkably, TFCM displayed a high selectivity in Cs+ adsorption with the presence of other cationic (K+, Na+, Ca2+, Mg2+). TFCM could easily be separated from water because of loading on the melamine sponges. Besides, the TFCM could maintain more than 78.1 % removal ratio of Cs+ after five adsorption-desorption cycles. Furthermore, the concentration of Cs+ could decrease to 10 μg/L from 20 mg/L with a prominent removal ratio of 99.95 %. Characterization results revealed that the adsorption process of Cs+ by TFCM was dominated by ion-exchange. In summary, the TFCM is a high selectivity, efficiently and easily separable adsorbent with excellent application prospects for removing Cs from radioactive wastewater.

Cation reactivity inhibits perovskite degradation in efficient and stable solar modules.

Perovskite solar modules (PSMs) show outstanding power conversion efficiencies (PCEs), but long-term operational stability remains problematic. We show that incorporating N,N-dimethylmethyleneiminium chloride into the perovskite precursor solution formed dimethylammonium cation and that previously unobserved methyl tetrahydrotriazinium ([MTTZ]+) cation effectively improved perovskite film. The in situ formation of [MTTZ]+ cation increased the formation energy of iodine vacancies and enhanced the migration energy barrier of iodide and cesium ions, which suppressed nonradiative recombination, thermal decomposition, and phase segregation processes. The optimized PSMs achieved a record (certified) PCE of 23.2% with an aperture area of 27.2 cm2, with a stabilized PCE of 23.0%. The encapsulated PSM retained 87.0% of its initial PCE after ~1900 hours of maximum power point tracking at 85°C and 85% relative humidity under 1.0-sun illumination.

Dual-functional additive of cesium ion for achieving ultrahigh efficiency of persistent phosphorescence in existing polymer-based materials

Dual-functional additive of cesium ion for achieving ultrahigh efficiency of persistent phosphorescence in existing polymer-based materials

Assessment of thermal-hydraulic-mechanical-chemical (THMC) performances of Ca-type bentonite-graphite mixtures as buffer materials for a high-level radioactive waste repository

The bentonite buffer material is the most important element of the engineered barrier system (EBS) used to dispose of high-level radioactive waste. Therefore, there are functional criteria or performance targets for the bentonite buffer material to maintain the long-term performance of the EBS for the entire disposal system. Thermal conductivity is a key parameter in the design of an EBS as it has the greatest influence on the buffer temperature. As the peak temperature of the buffer should not exceed the thermal design criterion, it is necessary to increase the thermal conductivity of the bentonite buffer material. Therefore, in this study, a small portion of graphite was added to Ca-type bentonite and thermal, hydraulic, and mechanical properties were measured separately, along with overall THMC (thermal-hydraulic-mechanical-chemical) properties. Additionally, while thermal conductivity was examined for varying graphite contents, other properties such as hydraulic conductivity, swelling pressure, and unconfined compressive strength were tested with a 3 % graphite addition. In particular, the thermal conductivity was measured for 3 % graphite addition to the pure bentonite under the different dry densities and saturation conditions and a regression analysis was performed to predict thermal conductivity based on the dry density and degree of saturation values. Furthermore, the saturated hydraulic conductivity, swelling pressure, unconfined compressive strength, and sorption efficiency of cesium (Cs) ions in bentonite and bentonite-graphite mixtures were measured. Moreover, prototype buffer blocks for bentonite-graphite mixtures were manufactured to evaluate viability of production. The addition of 3 % graphite to pure bentonite satisfied the functional criteria of saturated hydraulic conductivity and swelling pressure when the dry density was 1.63 g/cm3 or higher, and the thermal conductivity of the bentonite-3 % graphite mixtures was 10–30 % higher than that of pure bentonite.

Printing High‐Quality Formanidinum Lead Triiodide Films: Understanding the Critical Role of α‐Phase Nucleation Before Thermal Annealing

AbstractUpscaling the coating of formamidinium lead triiodide (FAPbI3) thin film is essential to realizing full printing and thereby roll‐to‐roll production of perovskite photovoltaics. However, thin‐film FAPbI3 processed from antisolvent‐free, printing methods suffer from undesirable degradation to the non‐photoactive phase, particularly in ambient processing conditions. Here, the most critical stage in thin‐film processing is identified as the gas‐quenching treatment of the as‐cast wet film. It is crucial to achieve both the nucleation of α‐phase nanocrystals and their sufficient growth at room temperature, which are indispensable for templating the growth of a highly crystalline and stable α‐FAPbI3 film during subsequent thermal annealing. The gas‐quenching‐treated film without these α‐phase nanocrystals can only be converted to meta‐stable α‐FAPbI3 by thermal annealing. By precisely identifying the spontaneous doping of cesium ion (Cs+) as a key factor in triggering α‐FAPbI3 nucleation and the role of chloride ion (Cl−) in enhancing nanocrystal growth, a generalized mechanism for additive engineering for the precursor ink is theorized. The identified mechanism translates to a power conversion efficiency of 19.36% for fully printed carbon‐electrode solar cells, 16.23% for carbon‐electrode minimodules, and excellent operational stability, showing the promising potential of this proposed fabrication route in the upscaling of perovskite photovoltaics.

Research Progress on the Extraction and Separation Technology of Rubidium and Cesium Ions

Research Progress on the Extraction and Separation Technology of Rubidium and Cesium Ions

Rapid and efficient separation of radioactive cesium ion/other radioactive ions by reduced graphene oxide membrane

Separation of cesium ions from other radioactive ions is of great significance for recycling and utilization of radioactive sources, facilitating the management of highly radioactive liquid waste (HLW), as well as for environmental protection. We achieved a highly selective and efficient separation of binary mixtures of 137Cs/60Co, Cs+/Co2+, Cs+/Ni2+, and Cs+/Zn2+ using amino-hydrothermal reduced graphene oxide membranes. The separation factor for non-radioactive binary mixtures is up to 4290, with a water permeance of 50.8 L m−2 h−1 bar−1. The separation factor for radioactive 137Cs/60Co is 623, which is somewhat underestimated due to the detection limit of the high-purity germanium spectrometer. The rGO membranes has the high water permeance of 72.4 L m−2 h−1 bar−1, with a thickness of ∼300 nm. The rGO membrane achieved effective separation of cesium and cobalt ions over a wide range of cesium-to-cobalt ion concentration ratios, with the best results achieved at a concentration ratio of 100:1 for cesium and cobalt. In addition, the rGO membranes showed outstanding stability. The superior performance is attributed to the amino hydrothermal treatment, which reduced oxygen functional groups and directly inserted nitrogen atoms into the GO lattice, ultimately forming stable narrow nanochannels conducive to the size-sieving effect. The findings show that the rGO membranes have excellent separation performance due to their size-sieving effect, and this work has great potential for rapid and efficient treatment of radioactive liquid waste.

Assessment of electrochemical removal mechanisms of diverse transition metal dichalcogenides for caesium ion removal in wastewater treatment

Abstract Effective treatment of radioactive wastewater is crucial for broader nuclear energy adoption, with caesium radionuclides (most exist in the form of caesium chloride) presenting challenges due to their long half-life and biological hazards. Conventional adsorbents like zeolites and carbon-based materials, including graphene, face limitations in adsorption capacity due to the formation of electric double layers (EDL). This has led to the investigation of alternatives such as transition metal dichalcogenides (TMDs) e.g., MoS2, MoSe2, and WSe2, which offer promising galleries for caesium ion removal. Aside from extensively studied MoS2, there is limited research on the adsorption mechanisms and capacities of other TMDs like MoSe2 and WSe2. Here, we conduct a comparative study examining the removal mechanisms and capacities of exfoliated MoS2, MoSe2, and WSe2 nanosheets, alongside an evaluation of these properties in relation to graphene. Our investigation reveals distinct removal mechanisms and capacities among these three materials for capturing caesium ions in a variety of mechanisms. MoS2 nanosheets primarily utilise a pseudocapacitive charge storage mechanism via intercalation, as evidenced by a total charge storage of 0.78 C g1, with only 2.6% stored via EDL formation. In contrast, MoSe2 predominantly relies on EDL formation, with almost 60% of the total 0.54 C g1 charge storage attributed to this mechanism. Lastly, WSe2 exhibits a combination of both charge storage behaviours, with a total charge storage of 0.77 C g1, of which 14% is due to EDL formation. This research highlights the potential efficacy of TMDs as viable materials for caesium removal, offering an appealing alternative to conventional adsorbents and likely fostering advancements in water treatment technologies.

Fabrication of graphene oxide/ammonium molybdophosphate composite membrane for decontamination of cesium ions from seawater

Efficient separation of radioactive cesium ions (Cs+) from complicated aqueous environmental media has attracted considerable interest, especially seawater. Ammonium molybdophosphate (AMP) is regarded as a promising adsorbent for Cs+, but its fine powder dramatically inhibits the potential for practical applications. Herein, graphene oxide (GO) was utilized as a support for the in-situ growth of AMP, and after vacuum filtration, GO/AMP composite membrane was successfully fabricated. It was found that the GO/AMP membrane exhibited excellent adsorptive filtration performance (47.3 L m−2h−1 bar−1 water flux and 99.2 % rejection for Cs+ with 20 ppm initial concentration, 30 mL feed solution). Influent pH and coexisting metallic ions had scarcely effects on Cs+ rejection. Over five cycles, the water permeability and Cs+ rejection remained essentially unchanged. Moreover, the decontamination of Cs+ from real seawater was demonstrated with the rejection ratio as high as 87.4 % and a relatively inhibitory flux of 14 L m−2h−1 bar−1. Based on FT-IR, XPS, and EXAFS analyzes, the rejection of Cs+ was mainly ascribed to the exchange of NH4+ in AMP with Cs+ in solution, and an inner-sphere coordination of Cs+ rather than a weak outer-sphere interaction between hydrated Cs+ ions and adsorbent occurred.

Rubidium and Cesium Ion-Induced Electron and Ion Signals for Scanning Ion Microscopy Applications.

Scanning ion microscopy applications of novel focused ion beam (FIB) systems based on ultracold rubidium (Rb) and cesium (Cs) atoms were investigated via ion-induced electron and ion yields. Results measured on the Rb+ and Cs+ FIB systems were compared with results from commercially available gallium (Ga+) FIB systems to verify the merits of applying Rb+ and Cs+ for imaging. The comparison shows that Rb+ and Cs+ have higher secondary electron (SE) yields on a variety of pure element targets than Ga+, which implies a higher signal-to-noise ratio can be achieved for the same dose in SE imaging using Rb+/Cs+ than Ga+. In addition, analysis of the ion-induced ion signals reveals that secondary ions dominate Cs+ induced ion signals while the Rb+/Ga+ induced signals contain more backscattered ions.

Fluorescence Light‐Up Electrospun Membrane Incorporated with PbBr2 as a Highly Selective Fluorescence Probe for the Detection of Cs+

AbstractThis study introduces a novel fluorescent light‐up electrospun membrane, integrating PbBr2, which serves as an exceptionally selective probe for the detection of cesium ions (Cs+). Leveraging the superior optical properties of CsPbBr3 perovskite nanocrystals (PNCs), the researchers employ electrospinning technology to fabricate a test strip, namely PbBr2@polyacrylonitrile (PbBr2@PAN) nanofiber membranes, capable of swiftly detecting Cs+ in water merely by observing changes in the nanocrystals' luminescence with the naked eye. By the introduction of NH4+‐modified montmorillonite (NH4+‐MMT), PbBr2‐MT@PAN nanofiber membranes is obtained. The selectivity and sensitivity to Cs+ can be further improved because NH4+‐MMT endows PbBr2‐MT@PAN nanofiber membranes with the hydrophilic property and selective adsorption toward Cs+ ions. The membrane's fabrication is simple, scalable, and cost‐effective, with high cesium selectivity and sensitivity down to 44 ppb. This innovation enables efficient, on‐site cesium monitoring critical for environmental safety and nuclear waste management.

Comparison of Adsorption Capacity of Natural and Acid-activated Kaolinite Clay for Cesium ions from Aqueous Solution

Objectives : This study is to compare the removal efficiency of cesium ions in aqueous solutions by natural and acid-activated kaolinite clay.Methods : Natural kaolinite clay was acid-treated with H2SO4 (2M) at 80oC for 6 h under mechanical stirring. While activating natural kaolinite clay with acid, cations such as Al3+, Ca2+, Mg2+ and Fe3+ were partially eluted from the crystal lattice of natural kaolinite clay, and resulted in the increase in the surface area and the pore volume through the opening of crystal lattice. The surface area and the pore volume of acid-activated kaolinite clay were found to be roughly three times higher than natural kaolinite clay. The characteristics of natural and acid-activated kaolinite clay were observed by X-ray Fluorescence Spectroscopy, Energy Dispersive X-ray Spectroscopy, and BET Surface Area Analyzer.Results and Discussion : Generally, adsorption efficiency of Cs+ ion by acid-activated kaolinite clay showed much higher compared with natural kaolinite clay. At 50 mg L-1 of Cs+ ion concentration and the unit of dose in g L-1 , the adsorption efficiencies of Cs+ ion by natural and acid-activated kaolinite clay were 57.5% and 96.9%, respectively. The data obtained from this study were fitted to the adsorption isotherm and the kinetic models, respectively. It revealed that the Langmuir isotherm and the pseudo-second-order kinetic models described well the adsorption behavior of Cs+ ions on both natural and acid-activated kaolinite clay owing to their higher correlation coefficient R2. Based on the Langmuir isotherm coefficient Q, adsorption capacity of Cs+ ion by natural kaolinite clay and acid-activated kaolinite clay were 5.65 mg g-1 and 10.6 mg g-1, respectively.Conclusion : The results demonstrated that acid-activated kaolinite clay with acid treatment can be used as more effective adsorbent for the adsorption of Cs+ ions from aqueous solution than natural kaolinite clay.

Synthesis of Jasminaldehyde (α-pentylcinnamaldehyde) using Cs-AlMCM-41 Nanoparticle as Heterogeneous Solid Base Catalyst

In this study, the ultra-small mesoporous Cs-AlMCM-41 nanoparticle materials were obtained with high specific BET surface areas in the range of 426 m2g-1 with 1.97 nm pore size. The pore volume was found to be 0.86 cm3. The material possesses a basic site due to caesium ions (Cs+) counterbalancing the negative rise by Al in the mesoporous framework. The basicity of the sample was found to be 115.48 mol g-1. The basicity was proven via the condensation reaction of heptanal and benzaldehyde using microwave irradiation with a microwave power of 800 W. The sample (Cs-MCM-41) gave a higher conversion of heptanal (73.8%) with (70.1%) selectivity to jasminaldehyde. The CsMCM-41 can be a promising base catalyst in aldol condensation reaction for the synthesis of jasminaldehyde under autogenous pressure. Hence, the solid catalyst is easily recycled up to five (5) times with minimal loss of activity due to washing.

Preparation of highly hydrophilic cesium ion sieve and its performance in adsorbing Cs+

The unique properties of cesium compounds have garnered increasing attention, among which Cs2Ti6O13 shows great potential for applications. This paper synthesized Cs2Ti6O13(CTO-3) using a template-assisted solvothermal method with cesium carbonate as the cesium source and tetrabutyl titanate as the titanium source. Among them, F127 and hexadecylamine are used as template agents to modulate the surface morphology and hydrophilicity of the precursor. The cesium ion sieve H2Ti6O13 (HTO-3) synthesized after hydrochloric acid pickling has a large specific surface area and good hydrophilicity. This structure is conducive to the ion exchange between Cs+ and H+, resulting in a fast adsorption rate. It is completed within 2 h, and the adsorption capacity reaches 360 mg/g, which is significantly greater than that of the traditional high-temperature solid-phase method. The adsorption process of Cs+ on HTO-3 is more consistent with the pseudo-second-order kinetic equation model, and the adsorption process is chemical adsorption. HTO-3 exhibited good selectivity and cycle stability. At the fifth time of the adsorption-resolution cycle, the adsorption capacity was 87.1 % of the first time.

REMOVAL OF RESIDUAL CONCENTRATIONS OF CESIUM IONS FROM LOW-LEVEL RADIOACTIVE SOLUTIONS

Because of mathematical modelling, the region of existence of the component composition of a complex inorganic sorbent designed to remove residual concentrations of cesium ions from low-level radioactive aqueous solutions was determined. The olay they limited by x1 – the number of nanoparticles of the iron oxide component from 18 to 19.5 ml, by x2 - the amount of copper ferrocyanide from 0.9 to 1.05 g, by x3 – the amount of Portland cement from 0.88 to 0.95 g. The determined concentrations of the complex inorganic sorbent provide for the removal of cesium ions from 98 to 100% and the capacity of the complex inorganic sorbent from 9 to 9.5 mg/g. According to the data on the frequencies of occurrence of the variation factors and their products in terms of their influence on the degree of cesium ion extraction from solution and the sorption capacity of the complex inorganic sorbent, they ranked in the following sequence, namely: х1х2х3>х1х2>х2х3>х1х3>х3>х2>х1. The influence of variation factors on other properties of the initial parameters is less relevant.

Efficient sequestration of cesium ions using phosphoric acid-modified activated carbon fibers from aqueous solutions

In this study, acid-modified activated carbon fibers (ACF-Ps) were synthesized by phosphorylation. Three different types of ACF-based adsorbents functionalized with PO43−, P2O74−, or P3O105− ions, namely, ACF-P1, ACF-P2, and ACF-P3, were prepared by phosphorylating ACF with trisodium phosphate (Na3PO4), sodium dihydrogen pyrophosphate (Na2H2P2O5), and sodium tripolyphosphate (Na5P3O10), respectively, and utilized as adsorbents to remove cesium ions (Cs+) from aqueous solutions. Among the tested adsorbents, ACF-P3 exhibited the highest Cs+ adsorption capacity of 37.59 mg g−1 at 25 °C and pH 7 which is higher than that of ACF (5.634 mg g−1), ACF-P1 (19.38 mg g−1), and ACF-P2 (30.12 mg g−1) under the same experimental conditions. More importantly, the Cs+ removal efficiencies of ACF-P3 (82.90%), ACF-P2 (66.2%), ACF-P1 (34.2%) were 29.3-, 23.4-, and 12.11-fold higher than that of un-treated ACF (2.83%). The results suggested that the phosphorylation with Na5P3O10 is highly suitable for Cs+ adsorption which effectively functionalizes ACF with a greater number of phosphate functional groups. Adsorption and kinetic data well-fitted the Langmuir isotherm and pseudo-second-order model, respectively, which indicated the monolayer adsorption of Cs+ onto ACF-P1, ACF-P2, and ACF-P3 which were largely controlled by chemisorption. Overall, phosphoric acids containing different phosphate-based polyanions (PO43−, P2O74−, or P3O105−) enriched –OH and/or –COOH surface functional groups of ACF in addition to P-containing surface groups (PO, C–P–O, C–O–P, and P–O) and facilitated the Cs+ adsorption through surface complexation and electrostatic interactions.

Cesium-doped manganese-based Prussian blue analogue as a high-efficiency cathode material for potassium-ion batteries

Prussian blue analogues (PBAs) are regarded as promising cathode materials for potassium-ion batteries (PIBs) owing to their low cost and high reversible capacity. Compared to other PBAs, potassium manganese hexacyanoferrate (KMnHCF) stands out for its superior capacity and operating voltage. However, Jahn-Teller effect of Mn3+ and the structural collapse caused by potassium ion insertion/extraction still affect the structural stability and electrochemical performance of this material. Herein, a green and efficient synthesis method is adopted to substitute potassium ions in KMnHCF with an appropriate amount of cesium ions to form a column effect. Cesium-doped KMnHCF (Cs-KMnHCF) mitigates the irreversible structural damage caused by potassiation/depotassiation and the Jahn-Teller effect, thereby improving the cycling stability. In addition, it widens the lattice channels, reduces the diffusion barrier of potassium ions, and optimizes the diffusion kinetics. By rationally controlling the doping amount of Cs+, the obtained K1.71Cs0.05Mn[Fe(CN)6]0.95·0.05·0.88H2O exhibits remarkable electrochemical performance, with an initial discharge capacity of 137.6 mA h g−1 at a current density of 20 mA g−1 and a capacity retention of 89.6% after 600 cycles at 200 mA g−1. More importantly, when assembled with a pitch-derived soft carbon anode, the full cell manifests excellent cycle stability and rate performance. This work is expected to provide a highly efficient cathode material for the practical application of PIBs.

Digital Twin Smart City: Integrating IFC and CityGML with Semantic Graph for Advanced 3D City Model Visualization

The growing interest in building data management, especially the building information model (BIM), has significantly influenced urban management, materials supply chain analysis, documentation, and storage. However, the integration of BIM into 3D GIS tools is becoming more common, showing progress beyond the traditional problem. To address this, this study proposes data transformation methods involving mapping between three domains: industry foundation classes (IFC), city geometry markup language (CityGML), and web ontology framework (OWL)/resource description framework (RDF). Initially, IFC data are converted to CityGML format using the feature manipulation engine (FME) at CityGML standard’s levels of detail 4 (LOD4) to enhance BIM data interoperability. Subsequently, CityGML is converted to the OWL/RDF diagram format to validate the proposed BIM conversion process. To ensure integration between BIM and GIS, geometric data and information are visualized through Cesium Ion web services and Unreal Engine. Additionally, an RDF graph is applied to analyze the association between the semantic mapping of the CityGML standard, with Neo4j (a graph database management system) utilized for visualization. The study’s results demonstrate that the proposed data transformation methods significantly improve the interoperability and visualization of 3D city models, facilitating better urban management and planning.

Radiation-induced grafting of polyethyleneimine onto cellulose triacetate membrane for separation of cesium ions from aqueous solution

Radiation grafting of polyethyleneimine (PEI) onto the surface of cellulose triacetate (CTA) membrane was successfully performed. Pre-radiation and co-radiation were applied by gamma rays at the dose of 12 kGy. FT-IR, SEM, XPS, contact angle, zeta-potential, grafting ratio, etc. Were used to characterize the PEI-CTA membranes before and after grafting. The FT-IR spectrum showed that a notable discernible shoulder peak of N–H appeared for amide at co-radiation and pre-radiation, and XPS analysis indicated that co-radiation achieved the highest N percent of 9.75%, suggesting that PEI was introduced into the membrane surface. In a forward osmosis (FO) process, the PEI-CTA membrane obtained higher cesium, Cs(I), retention (95–97%) than the CTA membrane with Cs(I) retention of 92%. Cs(I) fluxes significantly decreased from 0.09 to 0.02–0.03 mmol m−2h−1 after PEI modification. Effective Cs(I) retention was attributed to increase of the positive charges on CTA membrane when PEI was added, which exerted a repulsive effect on Cs(I), preventing them from moving towards the membrane direction. In the FO process, the PEI-CTA membrane featured the water flux of 23 L m−2 h−1 a little lower than that of CTA membrane (24 L m−2 h−1). Although modified PEI increased the hydrophilicity, the increase of water flux did not occur with the co-irradiated membrane, which was related to the high graft, higher thickness and resistance of the membrane.

Experimental investigation of electrostatic capture of 1+ ions in charge breeder electron cyclotron resonance ion source plasma

We present comprehensive experimental data demonstrating that the capture process of the 1+ ions in charge breeder electron cyclotron resonance ion sources (ECRIS) is dominated by electrostatic deceleration by the ambipolar plasma potential, not by cumulative small-angle scattering of the incident ions in ion–ion collisions as postulated previously. To achieve this we varied the plasma potential of an ECRIS charge breeder by adjusting the microwave power applied to sustain the helium discharge and measured the corresponding shift in the optimum injection energy of the 1+ ions. The experiment was repeated with sodium, potassium, and cesium ions. It is shown that the optimum injection energy does not depend on the incident ion mass, which contradicts the collisional drag model. Conversely, the optimum injection energy (in eV) shifts in unison with the plasma potential (in V), which provides strong evidence for the electrostatic deceleration hypothesis.